Add MULTI_NOZZLE_DUPLICATION test

buildroot/share/tests/megaatmega2560-tests

 opt_enable AUTO_BED_LEVELING_UBL RESTORE_LEVELING_AFTER_G28 DEBUG_LEVELING_FEATURE G26_MESH_EDITING ENABLE_LEVELING_FADE_HEIGHT SKEW_CORRECTION \
            EEPROM_SETTINGS EEPROM_CHITCHAT REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER SDSUPPORT GCODE_MACROS \
            USB_FLASH_DRIVE_SUPPORT SDCARD_SORT_ALPHA STATUS_MESSAGE_SCROLLING SCROLL_LONG_FILENAMES LIGHTWEIGHT_UI \
-           CUSTOM_USER_MENUS I2C_POSITION_ENCODERS BABYSTEPPING BABYSTEP_XY LIN_ADVANCE NANODLP_Z_SYNC QUICK_HOME JUNCTION_DEVIATION
+           CUSTOM_USER_MENUS I2C_POSITION_ENCODERS BABYSTEPPING BABYSTEP_XY LIN_ADVANCE NANODLP_Z_SYNC QUICK_HOME JUNCTION_DEVIATION MULTI_NOZZLE_DUPLICATION
 exec_test $1 $2 "Azteeg X3 with 5 extruders, RRDFGSC, probeless UBL, Linear Advance, and more"
 
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